Storage tank for petrol and like inflammable liquids



y 1933- J. F. MARTYN El AL 1,917,133

STORAGE TANK FOR PETROL AND LIKE INFLAMMABLE LIQUIDS Filed Dec. 15, 1930 J e A E m This:inventioii' relatee to";stor'ageltanks or "petrol and likeinfia'mmahle liquids -andghae. forv its 7 principal. object toiproyide an 511111 Tproved construction of tank wherebyiillage, loss by vaporization, and danger of .,;fire or "explosion, maybe IEGdllCBCiKtO-fijnilflifillllp and;

\ in}practice zentirelyobviated;

' In order to overcome thedisa 1 herent in the known-storage tanks;- wherein "is esiippl ied to the hot'toiiiofthe. tank; at, a suitable head :toxlensiire th'at thenpetrolor-1-r1.--.

1 flammable: liqiiid "fills vtheftankv right up to: i the roof, the petrol-or inflammable liquid vlee-.1,

withdrawn 'andfeupphediroin the top 'of,

' the tank Inanotherpropo'sediarifiangement;

' upstanding W331i." 0"rr1m 0f the Vesse'h thereby lowthe roof, it; has 'beempropbse the ipetrol gi or inflammable: liquid t-upon;v a

"dibe v i I ".ageta'nk forf' petrolor other nflaminahlejor' 'fvolatile liqiiidvis provided iwithflafiat oi I I arranged I or constructedftoiformi a, shafl1oIW;'-"

ultimately becornesfhighly i charged with Na pour; above theurface-iof theliqlii heavier and inertliqnidfsuohawater, Whiclri the inflammable liquidand is cap'ablei oflrisr ing 3 and fallin'gr iinder, the influence" of peratnre]: changes-foil the hulk of liquid :f-lil the tank. These proposed conetruo-tioi s are; effective to practical-1y elinii iaitelnllage lo s'ses ihyhevapo'ration; hiit there ,s'till gthe disadvantage that t'where. ithejiroof restingion' the liquid is; exposed; to the sun ori-lthezoiits'ide it becomes very bowed there is ajitendenc'y- I for; ,the liquid in contact "with the underside "of the roof tobecomedecompoeedfij Inthis} 7 connection it is" to be borne? in =min'd1 that petrol, which is the liqiiid chiefly under; cone v side'ratio n'; l is hot normally a" liquid "of zone density :but' iisiially a frniXtiire of spirits of varying dn'sities,;l.evaporatingipoirits:fand j i *characteristics;-=a-ndQeVeI under th e actionflof gravity. when standing" in} vstorage, '-fthere is 3a tendency for the heavier Spirits: to Settle: and

for the'ylighte'ri and more volatile spiriteto the'reforeof the rich r sipirits and'the'heating f desirable condition! as,

;'- separate the Volatiles, i

ing ao'tio'n of thezhot' roof is therefore an lin- J m? ET' m IKE A N'F MMABQ 1I I UIDS.

'ri f am:-so 4s 2 J r -i apour space betweeri the roo f and:v

'the'gsuij-iae oi-{thesli uid,,tospray-theexte ior, *ofvfthezr fg'and walls Withwa'ter for thevpurg",

dam? gas in-i "of a cololin gg iquid; such asjfwater; whichigis j j fiowsn-downkthe Walls "through,- a number a; film fof Water oyer the whole I of exterior 1 it surface of? the tankiwa'ilg r Conveniently; the water igsnpplied to thegvesseiby"meaneslic staiitiallyjconstant' levelggand "the lwatemadthat;the petroluror}"like liquid *isaike t up against,thennderside of the roof by; thexh'ead 5 I I OffWaterupon 'theiroof, Asthis'headissub tends further. tor V :ferredft mayh an dfin it)? M know 1 con ctioni ivvithj tanks having."

ose of keeping: thextemperature down; but! owing' to theunavoidable evaporationvinythe}; I 3 .dead?,space, -it isnot possihletofmaintain the" i'l k at a constanttemperature-byeuch m ans, 3 and means such aszan asop rator valve,* with resil l tarit losses and;sweating eina'lfl' holes] or "serrationsgor the like fin, the,

.ien suring substantially even} distribution. Qfi

yl-antageoi siy is supplied atlthe iceintre of the vessel'i or atone O IQI QQ IQ'pbsliimnsSo that"51f contlnuons cir'eulationmor.flow;"of aterqis 1: I

naintain'd inftheiiressel}towards: thefwall t to v a 'f lrtherfeature of the: in

st-a'ntially constant; i't provides j a convenient means for disch rging lt h'e -petrol" or the -like.

throughra-valiled outlet, pipe orthelike'comg rn'unicatingwith the topof just bef' heath the roof. coh'duit' or conduits re; 1 F

alvtes to enable thelcondu t or condults' to he "'The inveiition i ehereina fterdescribed b'y' 1 9 way"offegralnpleiiyith referenceito'the acco'm iag'r'amrnatio' drawingwhich is a,

. ti'onalkv w ill u st'rating aistoragetank in,

" 'ordan cewithfthegpresent invention/f 1 ln carryilig the invention ,intozefiect and-5,

so as to provide a shallow vessel 3 above the roof for the reception of cooling liquid, such as water, which is continuously supplied to the vessel 3 through a supply pipe 4 under the control of an automatic ball valve 5 of any suitable construction, the supply pipe 4 advantageously having a control valve 6. At a suitable height above the flat roof 2 the upstanding portion of the tank wall is perforated with a number of holes 7 or is formed in its upper edge with V grooves or the like so that the cooling liquid may overflow from the vessel 3 down the exterior of the wall 1 in the form of a continuous film, a collecting gutter 8 being provided around the :lower part of the tank by which the overflowing water is collected and carried away. By suchmeans the roof 2 is at all times insulated by the layer of cooling liquid which'is maintained thereon and thus cannot become overheated by the sun, while the wall of the tank is cooled by the continuous overflow from the vessel 8 through the perforations 7 or the like.

A conduit 9 leads from the bottom of the vessel 3 to a positiona short distance above the bottom 10 of the tank, such conduit 9 being provided with a control valve 11. 1k suitable depth of water-is always maintained in the bottom of the tank so that the petrol or like liquid stored therein'is floated upon such layer of water, the petrol or like liquid being introduced, for example, by means of a pipe 12 provided with a valve 13. The petrol or like liquid is withdrawn as required through a pipe 1e opening into the tank at a position immediately below the roof 2, such pipe 141- having a control valve 15. l/Vith this arrangement, it will be understood that by opening the valve 11 the head of water in the vessel 3 will act to raise the petrol or like liquid introduced into the tank right up to the underside of the'roof 2 so that there is no vapour space. During this operation any air or vapour trapped between thesurface of the petrol or like liquid and the roof 2 is permitted to escape through a gauging hatch 16, the cover 17 of which is thereafter replaced. As the petrol or like liquid is thus under the constant head of the liquid in the vessel 3, the pressure on the top of the roof 2 is compensated by the corresponding pressure on the underside thereof, while, by opening the valve 15, thepetrol or like liquid is delivered under a constant head through the pipe 14 as required. For the purpose of drawing off the water in the tank when it is required to refill the same with petrol or like liquid, a draw-oif pipe 18 provided with a valve 19 and communicating with a sump 20 is provided. By closingv the valve 11 and opening the valve 19, water in the tank is permitted to run out.

Any expansion of the stored petrol or like liquid will be relieved without any increase of pressure by the water being forced back through the conduit or conduits up to the roof top where it will escape by running down the sides. A. minimum. depth'of water of about six inches is normally maintainedin the bottom of the tank to allow for any expansion. 5 r

The cost of the water used in the plant will be negligible in comparison with the loss of petrol or the like duefto evaporation which normally would occur.

Furthermore, it is obvious that in the construction of tankaccording to the present invention, the roof and'walls may be very readily flooded to anydesired degree'in' case of fire. 'As the petrol or like liquid issues under substantially constant pressure at a suitable height, it will not require any mechanical handling before being sent to the barrelling plant and the latter, working under constant head, will be much better controlled.

In gauging the tank, it is only necessary to read the water level and subtract from the" known height of the tankwhich is always full up to the underside of the roof.

WVhat we claim is p In a storage tankfor inflammable or volatile liquids, a flat roof forming a shallow vessel, a float valve controlled inlet for supplying cooling liquid. to a pre-determined level in said vessel, there being perforations in the wall of the vessel maintaining a pre-determined head of cooling liquid in the vessel and permitting said liquid to overflow .down the exteriorof the tank wall, a valved conduit communicating with the bottom of the vessel and with the lower portion of the tank to supply the tank with liquid from the vessel so that the stored liquid in the tank is maintained against the underside of the roof by the head of liquid in the vessel abovethe roof, a valved outlet for the stored liquid in the tank communicating with the tank immediately below the roof, a valved inlet for said stored liquid communcating with the tank at a pre-determined level above the bottom thereof, a valved outlet communicating with the bottom of the tank, and a gauging hatch communicating with the tank underneath the bottom of the vessel for permitting the escape of entrapped air between the roof and the surface of the stored liquid within 

